This invention relates to recording disk cartridges and, more particularly, to a cartridge having a hub sealing arrangement for protection against contaminants when the cartridge is not in use.
Recording disk cartridges commonly are used in computer systems to provide a removably replaceable medium for the mass storage of data.
For computers employing 3.5 inch flexible magnetic disk drives, the disks are constructed of a thin sheet-like carrier, such as a polymeric film coated on its exterior surfaces with magnetic recording material such as a gamma ferric oxide, barium ferrite or the like. A rigid hub attached the center of the carrier of recording material permits connection of the disk to a drive which rotates the disk past one or more recording heads which serve to write magnetically data onto the disk and to read magnetically data from the disk. The disk is enclosed within a thin semi-rigid case having opposed walls with disk cleaning liners of soft nonwoven material disposed on opposite sides of the disk.
For other applications, such recording disk cartridges may employ a rigid magnetic disk or an optical data storage disk as the storage medium.
A disk cartridge, comprising a case with recording disk therein, is readily transported from one location to another. The previously mentioned 3.5 inch flexible magnetic cartridge is sufficiently small and thin so as to be carried in a person's shirt pocket. Recorded data is readily read from the disk, or is written or altered, by simply inserting the cartridge into a disk drive connected to a computer or other device which employs the data.
Disk drive components, such as the read/write heads and a hub engaging rotor for spinning the disk, obtain access to the disk through apertures provided in the walls of the case. For example, in a standard 3.5 inch flexible magnetic disk drive which is often employed for computer applications, the drive is provided with a rotor comprising a rotatable plate which abuts the disk hub and includes a central spindle which protrudes through a central aperture of the hub, and a pin which is offset from the spindle and engages within a pin receiving slot of the hub. The rotatable plate of the disk drive fits through an access opening in a bottom wall of the plastic case to engage with the hub, and lifts the hub away from peripheral portions of the access opening to free the disk for rotation between the liners of the case. If desired, a wear-resistant pad may be disposed on the inner surface of the top wall of the case to rest against the tip of the spindle, whereby the spindle serves to support the central portion of the top wall so as to overcome any warp in the semi-rigid plastic material of the upper wall and insure proper clearance for the disk between the case liners.
Access for the heads to interface with the disk is provided by a pair of radially extending slots formed, respectively, in the top and bottom walls in overlying registration with each other.
It is well known the dust, dirt, lint or other contaminants on the recording surfaces of the disk can lead to data read/write errors and, accordingly, the liners are provided to wipe the disk surfaces to remove contaminants as the disk rotates. To minimize entry of contaminants through the pair of head access slots when the cartridge is not located in a disk drive, the case is provided with a spring biased sliding shutter that automatically moves to a position covering the head access slots when the cartridge is removed from its operative position on the disk drive.
However, the disk contamination problem is not completely solved because the opening in the bottom wall allowing access of the rotatable drive plate to the hub, and the aperture in the center of the hub which receives the spindle can serve as entrances for contaminants, such as dust and lint, into the cartridge. Also, if the hub is constructed such that the offset slot for receiving the drive pin extends completely through the hub and is not otherwise closed, this slot provides yet another entrance for contaminants when the cartridge is not in use.